The field of the invention is utility poles, and the invention relates more particularly to the repair of weakened wooden utility poles.
Although wooden utility poles are typically treated with one or more preservatives, such poles often are subjected to rot, decomposition or insect or other wild life damage during the life of the pole. Most typically, this damage is of two types. The first is an exterior area of decomposition which is typically caused by chemical or mechanical action. Perhaps more common is an area of internal rot which forms in the center of the pole usually near or slightly below the ground line and this can weaken the pole to an extent where it must be replaced.
The replacement of utility poles is especially expensive in urban areas and is especially inconvenient when it is necessary to interrupt the power or telephone service on the pole in order to replace the pole with a new one. Thus, it is highly advantageous to repair the pole without removing it, and various methods are known to carry out such repair. For instance, U.S. Pat. No. 4,779,389 discloses a metal sleeve which is filled with a foaming composition. This patent cites numerous references which also relate to the problem. Many prior art methods provide a pole which is so strongly reinforced, as with a steel sleeve, that they, in turn, can provide a safety hazard. That is, if the pole is struck by a vehicle, it is preferably that the pole shear rather than cause massive damage to the vehicle. Therefore, it is preferable that the repair system leave the pole not greatly stronger than a new utility pole.
Another disadvantage of most prior art pole repair methods is the necessity of special equipment or specially trained personnel to carry out the repair steps. It would be highly advantageous if the pole inspection crew could carry out such process.
A further disadvantage of most prior art pole repair methods is that the repaired pole has a steel collar. Such steel collar makes it impossible for the standard metal spiked lineman's boots to be used to climb the pole. Instead, line maintenance workers must use lifting equipment to get above the metal jacketed repaired area.